The protein encoded by this gene is an oxidoreductase belonging to the copper type II, ascorbate-dependent monooxygenase family. It is present in the synaptic vesicles of postganglionic sympathetic neurons and converts dopamine to norepinephrine. It exists in both soluble and membrane-bound forms, depending on the absence or presence, respectively, of a signal peptide. [provided by RefSeq, Jul 2008].